Machine parts for engines, such as cylinder liners, piston rings and the like, are made from various kinds of materials. In particular, it is known to manufacture machine parts from gray iron due to its availability, relatively low cost, its recyclability, high conductivity and low shrinkage.
Typically, the machine parts are easily centrifugally cast from gray iron and exhibit good wear resistance. However, as-cast gray iron has significant drawbacks in that it is relatively weak and brittle in tension as a result of its microstructure. Further, graphite flakes present in the microstructure tend to be sharp and pointed, leading to stress concentration points when external tensile loads are exerted on the material.
To overcome the drawbacks in as-cast gray iron, it is known to alloy gray iron with high concentrations of molybdenum and nickel to produce a bainitic microstructure with increased wear resistance. However, alloying with molybdenum and nickel is expensive.
Other known abrasion resistant materials includes a gray iron that is formed with a pearlite matrix in the microstructure. One such example of this type of microstructure includes boron in very small amounts. The boron leads to the formation of carbide having high hardness, thereby increasing abrasion resistance. However, microstructures of pearlite only achieve a material hardness in the range of 212-248 BHN
Due to ever increasing production costs, there is a need for a low cost material that has significant material hardness levels and increased abrasion resistance from which machine component parts can be manufactured.